Vasopressin or antidiuretic hormone, the key hormone for our hydration

Vasopressin (also called arginine vasopressin or AVP and antidiuretic hormone or ADH) is a peptide hormone synthesized in the hypothalamus, then transported through axons(nerve fibres) to the posterior pituitary, which releases it into the blood. Osmolarity and volume status are the biggest factors that affect ADH secretion. 

Osmolality is a test that measures the concentration of all chemical particles found in the fluid part of blood. Normal serum osmolality ranges from about 285 to 300 milliosmoles per kilogram (mOsm/kg) in healthy people.

it plays essential roles in the control of the body’s osmotic balance and sodium homeostasis, tonicity homeostasis, blood pressure regulation and kidney functioning. Other stimuli of vasopressin release include painnausea, stresshypoglycemia, Diseases of the lungsnicotine, chest wallangiotensin IIhypothalamus, or pituitary gland and several drugs(like opiate drugs).

tonicity is The ability of an extracellular solution to make water move into or out of a cell by osmosis.

Osmosis is the movement of water through a semipermeable membrane from a region of low concentration to a region of high concentration, tending to equalise the concentrations of the water. Osmosis is passive transport, meaning it does not require energy to be applied.

Vasopressin is released in response to a decrease in blood volume. Specific pressure sensors called baroreceptors can detect arterial blood pressure.

it plays a major role in balancing osmolality and therefore in maintaining the capacity of water in the extracellular fluid (the fluid area that surrounds cells). This is crucial for protecting cells from sudden increases or decreases in water content, which may interfere with cell functioning. slight elevations in osmolarity result in the secretion of ADH. ADH then acts primarily in the kidneys to increase water reabsorption, thus returning the osmolarity to baseline.

ADH secretion is negatively affected by ethanol. Ethanol’s inhibitory effect helps to explain the increased diuresis experienced during intoxicated states as well as increased free water loss. without appropriate ADH secretion, the kidneys excrete more water.

If you don’t have enough vasopressin, your kidneys may excrete too much water. This causes frequent urination and can lead to dehydration, as well as low blood pressure. primary polydipsia (excessive water drinking) can also cause Low levels of anti-diuretic hormone. Diabetes insipidus is a condition where you either make too little anti-diuretic hormone (usually because of a tumour, trauma or inflammation of the pituitary or hypothalamus), or where the kidneys are insensitive to it. Diabetes insipidus is associated with increased thirst and urine production.

Secretion of anti-diuretic hormone can also occur if the concentration of salt in the bloodstream increases, for example as a result of not drinking enough water on a hot day. This is detected by special nerve cells in the hypothalamus which simulate anti-diuretic hormone release from the pituitary. hyponatraemia is a condition in which the concentration of salt reaches abnormally low levels.

foods like Smoked, cured, salted or canned meat, fish or poultry including bacon, cold cuts, ham, frankfurters, sausage, Pickles, sardines, Tortillas, Salad dressing, Broths and stocks, caviar and anchovies, Instant pudding, Cottage cheese, Frozen breaded meats and dinners, such as burritos, pizza, Canned entrees, such as ravioli, spam, chili and Salted nuts can increase the production of ADH.

vasopressin matters because By maintaining the appropriate volume of water in the space that surrounds cells within the body, vasopressin allows proper cellular function.
Vasopressin also plays a role in circadian rhythm(internal process that regulates the sleep–wake cycle and repeats on each rotation of the Earth roughly every 24 hours).
A condition called syndrome of inappropriate antidiuretic hormone secretion (SIADH) can occur when the body produces too much vasopressin.
In SIADH, excess water retention dilutes the blood, resulting in a low sodium concentration. Higher concentrations of anti-diuretic hormone cause blood vessels to constrict (become narrower) and this increases blood pressure.

Several disease states arise when the body loses control of ADH secretion or responds to its presence. ADH is stored in neurons within the hypothalamus. ADH promotes water reabsorption in the kidneys and at high concentrations and also will also cause vasoconstriction.

Both men and women naturally produce vasopressin, yet men experience its effects more strongly because of how it interacts with the male sex hormone testosterone.

the fast effect of a decrease in serum osmolality(for example overhydration) is the inhibition of the osmoreceptors. This inhibition leads to a decrease in vasopressin secretion and a therefore increase in water excretion. The osmoreceptors are also closely linked to the thirst, which is stimulated by high serum osmolality and is inhibited by low serum osmolality in the same way as is vasopressin secretion.